• Title/Summary/Keyword: 노드선택

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Speech enhancement based on reinforcement learning (강화학습 기반의 음성향상기법)

  • Park, Tae-Jun;Chang, Joon-Hyuk
    • Proceedings of the Korea Information Processing Society Conference
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    • 2018.05a
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    • pp.335-337
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    • 2018
  • 음성향상기법은 음성에 포함된 잡음이나 잔향을 제거하는 기술로써 마이크로폰으로 입력된 음성신호는 잡음이나 잔향에 의해 왜곡되어지므로 음성인식, 음성통신 등의 음성신호처리 기술의 핵심 기술이다. 이전에는 음성신호와 잡음신호 사이의 통계적 정보를 이용하는 통계모델 기반의 음성향상기법이 주로 사용되었으나 통계 모델 기반의 음성향상기술은 정상 잡음 환경과는 달리 비정상 잡음 환경에서 성능이 크게 저하되는 문제점을 가지고 있었다. 최근 머신러닝 기법인 심화신경망 (DNN, deep neural network)이 도입되어 음성 향상 기법에서 우수한 성능을 내고 있다. 심화신경망을 이용한 음성 향상 기법은 다수의 은닉 층과 은닉 노드들을 통하여 잡음이 존재하는 음성 신호와 잡음이 존재하지 않는 깨끗한 음성 신호 사이의 비선형적인 관계를 잘 모델링하였다. 이러한 심화신경망 기반의 음성향상기법을 향상 시킬 수 있는 방법 중 하나인 강화학습을 적용하여 기존 심화신경망 대비 성능을 향상시켰다. 강화학습이란 대표적으로 구글의 알파고에 적용된 기술로써 특정 state에서 최고의 reward를 받기 위해 어떠한 policy를 통한 action을 취해서 다음 state로 나아갈지를 매우 많은 경우에 대해 학습을 통해 최적의 action을 선택할 수 있도록 학습하는 방법을 말한다. 본 논문에서는 composite measure를 기반으로 reward를 설계하여 기존 PESQ (Perceptual Evaluation of Speech Quality) 기반의 reward를 설계한 기술 대비 음성인식 성능을 높였다.

The Performance Analysis of Nearest Neighbor Query Process using Circular Search Distance (순환검색거리를 이용하는 최대근접 질의처리의 성능분석)

  • Seon, Hwi-Joon;Kim, Won-Ho
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.1
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    • pp.83-90
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    • 2010
  • The number of searched nodes and the computation time in an index should be minimized for optimizing the processing cost of the nearest neighbor query. The Measurement of search distance considered a circular location property of objects is required to accurately select the nodes which will be searched in the nearest neighbor query. In this paper, we propose the processing method of the nearest neighbor query be considered a circular location property of object where the search space consists of a circular domain and show its performance by experiments. The proposed method uses the circular minimum distance and the circular optimal distance which are the search measurements for optimizing the processing cost of the nearest neighbor query.

A weight-based cluster head replacement algorithm in the Internet of Things (사물인터넷에서 가중치 기반 클러스터 헤드 교체 알고리즘)

  • Kim, Jeong-Won
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.11
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    • pp.91-96
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    • 2014
  • Since the sensors of Internet of Things (IOT) collect various data, the lifetime of sensor network is very important and the data should be aggregated efficiently. The contiguous collection by the certain sensors occurs an excessive battery consumption and successive transmission of same value of data should be avoided. To solve these things, we propose an weight-based cluster head replacement method that divides whole network into several grids and cluster head is selected by remaining energy, density of alive sensors and location of sensor. The aim of algorithm maximizes the lifetime of network. Our simulation results shows that the proposed method is very simple as well as balances energy consumption.

A study on Stage-Based Flow Graph Model for Expressing Cyber Attack Train Scenarios (사이버 공격 훈련 시나리오 표현을 위한 Stage 기반 플로우 그래프 모델 연구)

  • Kim, Moon-Sun;Lee, Man-Hee
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.31 no.5
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    • pp.1021-1030
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    • 2021
  • This paper proposes S-CAFG(Stage-based Cyber Attack Flow Graph), a model for effectively describing training scenarios that simulate modern complex cyber attacks. On top of existing graph and tree models, we add a stage node to model more complex scenarios. In order to evaluate the proposed model, we create a complicated scenario and compare how the previous models and S-CAFG express the scenario. As a result, we confirm that S-CAFG can effectively describe various attack scenarios such as simultaneous attacks, additional attacks, and bypass path selection.

Q-learning based packet scheduling using Softmax (Softmax를 이용한 Q-learning 기반의 패킷 스케줄링)

  • Kim, Dong-Hyun;Lee, Tae-Ho;Lee, Byung-Jun;Kim, Kyung-Tae;Youn, Hee-Yong
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2019.01a
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    • pp.37-38
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    • 2019
  • 본 논문에서는 자원제한적인 IoT 환경에서 스케줄링 정확도 향상을 위해 Softmax를 이용한 Q-learning 기반의 패킷 스케줄링 기법을 제안한다. 기존 Q-learning의 Exploitation과 Exploration의 균형을 유지하기 위해 e-greedy 기법이 자주 사용되지만, e-greedy는 Exploration 과정에서 최악의 행동이 선택될 수도 있는 문제가 발생한다. 이러한 문제점을 해결하기 위해 본 연구에서는 Softmax를 기반으로 다중 센서 노드 환경에서 데이터 패킷에 대한 Quality of Service (QoS) requirement 정확도를 높이기 위한 연구를 진행한다. 이 때 Temperature 매개변수를 사용하는데, 이는 새로운 정책을 Explore 하기 위한 매개변수이다. 본 논문에서는 시뮬레이션을 통하여 제안된 Softmax를 이용한 Q-learning 기반의 패킷 스케줄링 기법이 기존의 e-greedy를 이용한 Q-learning 기법에 비해 스케줄링 정확도 측면에서 우수함을 보인다.

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Secrecy Performance Evaluation of OSTBC using One-Bit Feedback in Correlated MIMO Channels (상관관계를 갖는 MIMO 채널에서 하나의 피드백 비트를 이용한 OSTBC의 물리계층 보안 성능 평가)

  • Lee, Sangjun;Lee, In-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.10a
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    • pp.886-889
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    • 2014
  • In this paper, we evaluate a physical layer security performance of orthogonal space-time block code(OSTBC) using one-bit feedback in the presence of an eavesdropper in wiretap channels, where we assume spatially correlated MIMO(multiple-input multiple-output) channels. In this paper, we present the one-bit feedback based OSTBC(F-OSTBC) scheme and compare security outage performances of F-OSTBC, conventional OSTBC, and transmission antenna selection schemes for various spatial correlation conditions at each node.

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Advanced AODV Routing Performance Evaluation in Vehicular Ad Hoc Networks (VANET에서 Advanced AODV 라우팅 성능평가)

  • Lee, Jung-Jae;Lee, Jung-Jai
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.6
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    • pp.1011-1016
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    • 2020
  • Rapid change in network topology in high-speed VANET(: Vehicular Ad Hoc Network) is an important task for routing protocol design. Selecting the next hop relay node that affects the performance of the routing protocol is a difficult process. The disadvantages of AODV(: Ad Hoc On-Demand Distance Vector) related to VANET are end-to-end delay and packet loss. This paper proposes the AAODV (Advanced AODV) technique to reduce the number of RREQ (: Route Request) and RREP (: Route Reply) messages by modifying the AODV routing protocol and adding direction parameters and 2-step filtering. It can be seen that the proposed AAODV reduces packet loss and minimizes the effect of direction parameters, thereby increasing packet delivery rate and reducing end-to-end delay.

The Concentric Clustering Method based on Fuzzy Logic in Sensor Networks (센서 네트워크에서 퍼지 이론 기반의 동심원 형태 클러스터링 방법)

  • Choi, Jin-Young;Jung, Sung-Min;Han, Young-Ju;Kim, Jong-Myoung;Chung, Tai-Myoung
    • Proceedings of the Korea Information Processing Society Conference
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    • 2008.05a
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    • pp.710-713
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    • 2008
  • 센서 네트워크는 습도, 온도, 조도 등의 다양한 정보를 수집할 수 있는 센서들을 특정한 지역이나 광범위한 지역에 분포하여 특정 이벤트를 탐지하거나 계속적으로 환경을 관찰하여 수집된 정보를 효율적으로 Base Station으로 전송하는 일종의 애드 혹 네트워크이다. 본 논문은 센서 네트워크의 라우팅 프로토콜 중 PEGASIS와 동심원 형태의 클러스터링 방법에 대해 취약점을 알아보고, 이를 해결하기 위한 방법으로 클러스터 헤드 선출을 위한 두 가지 기준을 정하고, 퍼지 이론을 기반으로 적절한 선택 값을 도출하여 효율적인 클러스터 헤드를 선출하는 방법을 제안한다. 이 방법은 각 센서 노드들의 남아있는 에너지를 고려할 수 있으며, 각 레벨에서 클러스터 헤드들은 가깝게 위치하게 되어 Multi-hop으로 데이터 전송 시 기존의 방법들보다 전송 거리를 줄일 수 있는 장점을 가지고 있다.

Low Cost and Acceptable Delay Unicast Routing Algorithm Based on Interval Estimation (구간 추정 기반의 지연시간을 고려한 저비용 유니캐스트 라우팅 방식)

  • Kim, Moon-Seong;Bang, Young-Cheol;Choo, Hyun-Seung
    • The KIPS Transactions:PartC
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    • v.11C no.2
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    • pp.263-268
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    • 2004
  • The end-to-end characteristic Is an important factor for QoS support. Since network users and required bandwidths for applications increase, the efficient usage of networks has been intensively investigated for the better utilization of network resources. The distributed adaptive routing is the typical routing algorithm that is used in the current Internet. The DCLC(Delay Constrained 1.east Cost) path problem has been shown to be NP-hard problem. The path cost of LD path is relatively more expensive than that of LC path, and the path delay of LC path is relatively higher than that of LD path in DCLC problem. In this paper, we investigate the performance of heuristic algorithm for the DCLC problem with new factor which is probabilistic combination of cost and delay. Recently Dr. Salama proposed a polynomial time algorithm called DCUR. The algorithm always computes a path, where the cost of the path is always within 10% from the optimal CBF. Our evaluation showed that heuristic we propose is more than 38% better than DCUR with cost when number of nodes is more than 200. The new factor takes in account both cost and delay at the same time.

Major Class Recommendation System based on Deep learning using Network Analysis (네트워크 분석을 활용한 딥러닝 기반 전공과목 추천 시스템)

  • Lee, Jae Kyu;Park, Heesung;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.27 no.3
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    • pp.95-112
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    • 2021
  • In university education, the choice of major class plays an important role in students' careers. However, in line with the changes in the industry, the fields of major subjects by department are diversifying and increasing in number in university education. As a result, students have difficulty to choose and take classes according to their career paths. In general, students choose classes based on experiences such as choices of peers or advice from seniors. This has the advantage of being able to take into account the general situation, but it does not reflect individual tendencies and considerations of existing courses, and has a problem that leads to information inequality that is shared only among specific students. In addition, as non-face-to-face classes have recently been conducted and exchanges between students have decreased, even experience-based decisions have not been made as well. Therefore, this study proposes a recommendation system model that can recommend college major classes suitable for individual characteristics based on data rather than experience. The recommendation system recommends information and content (music, movies, books, images, etc.) that a specific user may be interested in. It is already widely used in services where it is important to consider individual tendencies such as YouTube and Facebook, and you can experience it familiarly in providing personalized services in content services such as over-the-top media services (OTT). Classes are also a kind of content consumption in terms of selecting classes suitable for individuals from a set content list. However, unlike other content consumption, it is characterized by a large influence of selection results. For example, in the case of music and movies, it is usually consumed once and the time required to consume content is short. Therefore, the importance of each item is relatively low, and there is no deep concern in selecting. Major classes usually have a long consumption time because they have to be taken for one semester, and each item has a high importance and requires greater caution in choice because it affects many things such as career and graduation requirements depending on the composition of the selected classes. Depending on the unique characteristics of these major classes, the recommendation system in the education field supports decision-making that reflects individual characteristics that are meaningful and cannot be reflected in experience-based decision-making, even though it has a relatively small number of item ranges. This study aims to realize personalized education and enhance students' educational satisfaction by presenting a recommendation model for university major class. In the model study, class history data of undergraduate students at University from 2015 to 2017 were used, and students and their major names were used as metadata. The class history data is implicit feedback data that only indicates whether content is consumed, not reflecting preferences for classes. Therefore, when we derive embedding vectors that characterize students and classes, their expressive power is low. With these issues in mind, this study proposes a Net-NeuMF model that generates vectors of students, classes through network analysis and utilizes them as input values of the model. The model was based on the structure of NeuMF using one-hot vectors, a representative model using data with implicit feedback. The input vectors of the model are generated to represent the characteristic of students and classes through network analysis. To generate a vector representing a student, each student is set to a node and the edge is designed to connect with a weight if the two students take the same class. Similarly, to generate a vector representing the class, each class was set as a node, and the edge connected if any students had taken the classes in common. Thus, we utilize Node2Vec, a representation learning methodology that quantifies the characteristics of each node. For the evaluation of the model, we used four indicators that are mainly utilized by recommendation systems, and experiments were conducted on three different dimensions to analyze the impact of embedding dimensions on the model. The results show better performance on evaluation metrics regardless of dimension than when using one-hot vectors in existing NeuMF structures. Thus, this work contributes to a network of students (users) and classes (items) to increase expressiveness over existing one-hot embeddings, to match the characteristics of each structure that constitutes the model, and to show better performance on various kinds of evaluation metrics compared to existing methodologies.